Class: Mammoth::PersistedPayloadDeserializer

Inherits:
Object
  • Object
show all
Defined in:
lib/mammoth/persisted_payload_deserializer.rb

Overview

Reconstructs exact CDC core work items from persisted webhook payloads.

Dead letters and sample files contain Mammoth's JSON delivery projection, not live CDC objects. This class is the explicit boundary that converts those persisted representations back into core vocabulary.

Class Method Summary collapse

Class Method Details

.event(payload) ⇒ CDC::Core::ChangeEvent

Deserialize one persisted event payload.

Parameters:

  • payload (Hash) —

    Mammoth event payload

Returns:

  • (CDC::Core::ChangeEvent) —

    reconstructed core event



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# File 'lib/mammoth/persisted_payload_deserializer.rb', line 17

def event(payload)
  attributes = stringify_keys(payload)
  data = attributes["data"]
  metadata = enriched_metadata(attributes)

  CDC::Core::ChangeEvent.new(
    operation: attributes.fetch("operation"),
    schema: attributes["namespace"] || attributes.fetch("schema"),
    table: attributes["entity"] || attributes.fetch("table"),
    old_values: attributes["old_values"] || delete_values(attributes, data),
    new_values: attributes["new_values"] || changed_values(attributes, data),
    primary_key: attributes["identity"] || attributes["primary_key"],
    transaction_id: attributes["transaction_id"],
    commit_lsn: attributes["commit_lsn"] || attributes["source_position"],
    sequence_number: attributes["sequence_number"],
    occurred_at: parse_time(attributes["occurred_at"]),
    metadata: metadata
  )
rescue KeyError, ArgumentError, TypeError => e
  raise ConfigurationError, "invalid persisted CDC event: #{e.message}"
end

.transaction(payload) ⇒ CDC::Core::TransactionEnvelope

Deserialize one persisted transaction payload.

Parameters:

  • payload (Hash) —

    Mammoth transaction webhook payload

Returns:

  • (CDC::Core::TransactionEnvelope) —

    reconstructed core transaction



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# File 'lib/mammoth/persisted_payload_deserializer.rb', line 43

def transaction(payload)
  attributes = stringify_keys(payload)
  CDC::Core::TransactionEnvelope.new(
    transaction_id: attributes.fetch("transaction_id"),
    events: attributes.fetch("events").map { |event_payload| event(event_payload) },
    commit_lsn: attributes["commit_lsn"] || attributes["source_position"],
    committed_at: parse_time(attributes["committed_at"]),
    metadata: enriched_metadata(attributes)
  )
rescue KeyError, ArgumentError, TypeError => e
  raise ConfigurationError, "invalid persisted CDC transaction: #{e.message}"
end